Cultures that tolerated certain behaviors were less likely to survive than cultures that suppressed certain behaviors. After millennia, the traditions of surviving cultures represent a large amount of institutionalized wisdom on how to conduct a lasting society.
Yes. And the Founding Fathers did a pretty great job codifying the lessons learned through the ages, and through the judeo/christian principles of the Bible, into a cohesive philosophy of governing provided in the Declaration of Independence, the Constitution, Federalist Papers, etc.
It is the greatest "plan" humans have ever made, IMO, and it is based on the best understanding and selective use of that institutionalized wisdom you speak of.